Oxytocin antagonism reverses the effects of high estrogen levels and oxytocin on decidualization and cyclooxygenase activity in endometrial tissues

ABSTRACT Research Question What is the in vitro effect of oxytocin receptor (OTR) antagonism on parameters of receptivity in human endometrial explants and endometrial cell line cultured in Estradiol (E 2 ) rich conditions mimicking Controlled Ovarian Hyperstimulation. Design Experimental in vitro study on endometrial tissues explants collected by aspiration biopsy from 30 women undergoing fertility treatment and cultured endometrial tHESC cell line. Study examined effects of high E 2 , Oxytocin (OT) and OTR antagonist on parameters of decidualisation (cells viability and secreted prolactin) as well as Cyclooxygenase-1/2 (COX-1/2) activity and Prostaglandin F 2α (PGF 2α ) secretion. Changes in expression of OTRs and COX-2 synthase genes were examined with quantitative Polymerase Chain Reaction (qPCR). Results Both high E 2 and OT limited endometrial viability and decidualisation and augmented endometrial COX-2 activity and formation of PGF 2α . All these effects were reversed by OT antagonist. Conclusions OT antagonist reversed the effects of high E 2 and OT on parameters related to endometrial receptivity. This might point to an additional mechanism of support of embryo implantation in the application of oxytocin antagonists prior to embryo transfer.